Method for depositing fluorine doped silicon dioxide films

Abstract

A process of preparing a moisture-resistant fluorine containing silicon oxide film includes steps of supplying reactant gases containing silicon, oxygen and fluorine into a process chamber and generating plasma in the process chamber, supporting a substrate on a substrate support in the process chamber and growing a fluorine-containing silicon oxide film on the substrate by contacting the substrate with the plasma while maintaining temperature of the film above 300 DEG C. The silicon and fluorine reactants can be supplied by separate gases such as SiH4 and SiF4 or as a single SiF4 gas and the oxygen reactant can be supplied by a pure oxygen gas. The SiH4 and SiF4 can be supplied in a gas flow ratio of SiH4/(SiH4+SiF4) of no greater than 0.5. The process can provide a film with a fluorine content of 2-12 atomic percent and argon can be included in the plasma to assist in gap filling. The plasma can be a high density plasma produced in an ECR, TCP TM , or ICP reactor and the substrate can be a silicon wafer including one or more metal layers over which the fluorine-containing silicon oxide film is deposited. The substrate support can include a gas passage which supplies a temperature control gas into a space between opposed surfaces of the substrate and the substrate support for maintaining the substrate at a desired temperature.

What is claimed is: 
     
       1. A process of preparing a moisture-resistant fluorine-containing silicon oxide film, comprising steps of: supplying reactant gases containing silicon, oxygen and fluorine into a process chamber and generating plasma in the process chamber, the reactant gases including SiF 4  and SiH 4  in a SiH 4  /(SiH 4  +SiF 4 ) gas flow ratio;   supporting a substrate on a substrate support; and   growing the fluorine-containing silicon oxide film on the substrate by contacting the substrate with the plasma while maintaining temperature of the growing film above 300° C., the temperature of the growing film being controlled as a function of the SiH 4  /(SiH 4  +SiF 4 ) gas flow ratio so that the growing film is moisture resistant, the growing film having a fluorine content of 2 to 12 atomic %.   
     
     
       2. The process of claim 1, wherein the reactant gases consist of the SiF 4  and SiH 4  gases. 
     
     
       3. The process of claim 2, wherein the SiF 4  and SiH 4  gases are supplied into the process chamber in a gas flow ratio of SiH 4  /(SiH 4  +SiF 4 ) of less than 0.5. 
     
     
       4. The process of claim 3, wherein the temperature of the film is controlled as a function of fluorine content of the film, the temperature being lower for higher fluorine content films. 
     
     
       5. The process of claim 4, wherein during the growing step the temperature of the film is maintained no lower than 360° C. and the gas flow ratio of SiH 4  /(SiH 4  +SiF 4 ) is no greater than 0.4. 
     
     
       6. The process of claim 4, wherein during the growing step the temperature of the film is maintained no lower than 320° C. and the gas flow ratio of SiH 4  /(SiH 4  +SiF 4 ) is no greater than 0.3. 
     
     
       7. The process of claim 1, wherein the process is a gap filling process wherein the silicon oxide film is deposited in gaps between electrically conductive lines on the substrate, the gas containing argon in an amount sufficient to assist in gap filling. 
     
     
       8. The process of claim 1, wherein the plasma is a high density plasma. 
     
     
       9. The process of claim 8, wherein the process is carried out in the process chamber of an electron cyclotron resonance plasma apparatus. 
     
     
       10. The process of claim 8, wherein the process is carried out in the process chamber of inductively coupled plasma apparatus. 
     
     
       11. The process of claim 1, wherein the substrate is a semiconductor wafer. 
     
     
       12. The process of claim 1, wherein the film is deposited over a metal layer. 
     
     
       13. The process of claim 1, wherein the substrate support includes a gas passage supplying a temperature control gas into a space between opposed surfaces of the substrate and the substrate support. 
     
     
       14. A process of preparing a moisture-resistant fluorine-containing silicon oxide film, comprising steps of: supplying reactant gases containing silicon, oxygen and fluorine into a process chamber and generating plasma in the process chamber;   supporting a substrate on a substrate support; and   growing the fluorine-containing silicon oxide film on the substrate by contacting the substrate with the plasma while maintaining temperature of the growing film above 300° C., the reactant gases including SiF 4  and SiH 4  supplied in a gas flow ratio of SiH 4  /(SiH 4  +SiF 4 ) of less than 0.5 and the plasma being a high density plasma, the temperature of the growing film being controlled as a function of the fluorine content of the growing film so that the growing film is moisture resistant, and the growing film having a fluorine content of 2 to 12 atomic %.   
     
     
       15. The process of claim 14, wherein the silicon oxide is deposited during a gap filling process. 
     
     
       16. The process of claim 14, wherein the substrate support includes an electrode applying a radio frequency bias to the substrate.